The present invention relates to suspension systems for commercial vehicles.
Several suspension systems have been developed which improve the ability a vehicles rear wheels to track the front wheels of the vehicle as it takes a turn around a sharp corner. For example, U.S. Pat. No. 5,220,972 issued to the present inventor on Jun. 22, 1993 (hereinafter the ""972 patent) discloses a suspension system for permitting the self-tracking of rear axles by the use of angled torsion rods coupled with means for permitting non-powered lateral deflection of the suspension type employed on the vehicle. With the suspension system of the ""972 patent, the rear tires rotate closely along the line of travel of the front tires such that the rear tires track around the corner thereby allowing the driver to safely negotiate a turn without having to use two lanes of traffic. Such conventional suspension systems although operable with significant success may not be cost effective to manufacture and install on all types of vehicles.
One object of the present invention to provide a kit to easily and cost effectively retrofit old vehicles with a suspension system that cause the rear tires to rotate closely along the line of travel of the front tires such that the rear tires track around the corner thereby allowing the driver to safely negotiate a turn without having to use two lanes of traffic.
The present invention is a suspension system for use with a trailer or truck having a frame and front and rear axles. In one embodiment, the suspension system comprises a front hanger having a lower portion, a bearing portion, and an upper portion engaged with the frame. The suspension system further comprises a hanger assembly having a lower portion, an upper portion engaged with the frame and a rocker arm having first and second bearing portions. The suspension system further comprises a rear hanger engaged with the frame and having a bearing portion. The suspension system further comprises a first saddle engaged with the front axle and a second saddle engaged with the rear axle. The suspension system further comprises a leaf spring having a first end portion engaged with the bearing portion of the front hanger and a second end portion engaged with the first bearing portion of the rocker arm. The suspension system further comprises a torque bar having a first end portion engaged with the front hanger and a second end portion engaged with the first saddle of the front axle. The suspension system further comprises a leaf spring assembly comprising an upper leaf spring having a first end portion engaged with the second bearing portion of the rocker arm and a second end portion engaged with the bearing portion of the rear hanger. The first and second end portions of the upper leaf spring have a width that is substantially less than the width of the second bearing portion of the rocker arm and the bearing portion of the rear hanger. The suspension system further comprises a torque bar assembly having a first end portion engaged with the hanger and rocker assembly and a second end portion engaged with the second saddle of the rear axle.